A wireless network, such as a cellular network, can include an access node (e.g., base station) serving a number of wireless devices or user equipment (UE) in a geographical area covered by a radio frequency transmission provided by the access node. Data may be communicated between the access node and the wireless devices on a plurality of frequency bands. A frequency band may be composed of one or more frequency sub-bands or component carriers each having a certain bandwidth (e.g., 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, or other suitable bandwidths). A wireless device may be configured to receive or transmit data on one or more component carriers of the frequency band. To increase bandwidth and data transmission rate, wireless networks may implement carrier aggregation to aggregate two or more component carriers from different frequency bands (i.e., inter band carrier aggregation) or from the same band (i.e., intra band carrier aggregation). Carrier aggregation can increase the bandwidths and transmission rates.
When multiple frequency bands are used in a wireless network, each frequency band has a coverage area. In generally, lower frequency bands have larger coverage areas that can reach wireless devices at further distances from the access node. Higher frequency bands have smaller coverage areas that can reach wireless devices at shorter distances from the access node.
The wireless network may support a plurality of modulation schemes, such as Quadrature Phase Shift Keying (QPSK), and Quadrature Amplitude Modulation (QAM). QPSK enables data to be transmitted at 2 bits per symbol with one of four possible carrier phase shifts (0, 90, 180, or 270 degrees). QAM combines two amplitude-modulated carrier waves into a single channel, thereby doubling the effective bandwidth. Various forms of QAM may be used, including, for example, 4 QAM, 16 QAM, 64 QAM, and 256 QAM. The numbers 4, 16, 64, and 256 indicate the numbers of points used in a constellation diagram for the QAM, as known in the art. The higher the number, the higher the order of modulation, and the higher the data transmission rate (e.g., more bits per symbol). For example, 4 QAM enables a data transmission rate of 2 bits per symbol, which is equivalent to the data rate of QPSK, 16 QAM enables a data transmission rate of 4 bits per symbol, and 64 QAM enables a data transmission rate of 6 bits per symbol, and 256 QAM enables a data transmission rate of 8 bits per symbol.
A higher-order modulation scheme requires a higher signal-to-interference-plus-noise-ratio (SINR) because a higher-order modulation scheme is susceptible to errors and/or packet loss due to lower robustness or reliability. Therefore, a higher-order modulation scheme is typically invoked or used only when the radio frequency condition satisfies a predetermined criterion. For example, 256 QAM may be invoked only in excellent radio frequency conditions, e.g., when SINR is equal to or above a threshold level, for example, 22 dB. In order to have a SINR meeting the 22 dB threshold, a wireless device has to be close to the base station. Thus, oftentimes, 256 QAM is invoked only when wireless devices are close to the access node. As a result, 256 QAM may rarely be invoked.
Because a higher-order modulation scheme is not invoked sufficiently, resources and capacity of the wireless network are wasted, resulting in low spectral efficiency and poor performance. Therefore, there is a need for systems and methods that can improve the spectral efficiency and/or network performance of the wireless network.
Overview
Exemplary embodiments described herein include systems, methods, and processing nodes for dynamic inter band carrier aggregation. An exemplary system described herein for inter band carrier aggregation includes an access node configured to deploy a radio air interface to provide wireless services to a plurality of wireless devices. The access node includes a processor configured to determine a location of a wireless device. The processor is also configured to compare the location of the wireless device with predetermined map data to determine whether the wireless device is located within an overlapping area between a first coverage area of a first modulation scheme on a first frequency band and a second coverage area of a second modulation scheme on a second frequency band. The processor is further configured to, when the wireless device is located within the overlapping area, perform an inter band carrier aggregation between the first frequency band and the second frequency band for the wireless device.
An exemplary method described herein for inter band carrier aggregation includes determining, by a processor, a location of a wireless device. The method also includes comparing, by the processor, the location of the wireless device with predetermined map data to determine whether the wireless device is located within an overlapping area between a first coverage area of a first modulation scheme on a first frequency band and a second coverage area of a second modulation scheme on a second frequency band. The method further includes when the wireless device is located within the overlapping area, performing, by the processor, an inter band carrier aggregation between the first frequency band and the second frequency band for the wireless device.
An exemplary processing node described herein for inter band carrier aggregation is configured to perform various operations. The operations include determining a spectral efficiency based on data transmitted between an access node and a plurality of wireless devices. The operations also include comparing the spectral efficiency with a predetermined efficiency threshold. The operations further also include when the spectral efficiency is equal to or lower than the predetermined efficiency threshold, determining whether a wireless device operating on a first frequency band using a first modulation scheme is located within an overlapping area between a first coverage area of the first modulation scheme on the first frequency band and a second coverage area of a second modulation scheme on a second frequency band. The operations further include when the wireless device is located within the overlapping area, performing an inter band carrier aggregation between the first frequency band and the second frequency band for the wireless device.